Dead PC - repair or buy new?

I would appreciate advice. My Multi-vision PC is 4 years old and suddenly I have stopped getting any signal to my screen - in fact I don't even get the beep when it starts to boot. I have followed the advice in the forum and with only the motherboard, power supply and CPU connected I still do not get any beep. I have checked the power output and all of the voltages appear to be there. It just doesn't want to boot up.

Can anyway offer advice whether I should throw it away and get a new one, or should I pay for the parts to repair it?

I have a MSI KT3 Ultra 2 motherboard, with an AMD Athlon XP 2200+ CPU.

The screen is an iiyama 19" vision master pro that I am really pleased with

It might be that the CPU has blown,or become misaligned with the heat sink,try removing it and re-seating.You will need to apply new thermal paste if you do this.I presume the CPU/PSU fan's work when you turn it on.

Yes the fan is working ok. I wouldn't have thought it was a misaligned heat sink as it doesn't even boot so wouldn't have had time to overheat. Could reseating really help? It has worked fine for 4 years.

Try looking on the motherboard for a jumper that says "Clear CMOS", usually a set of three pins connected to pins 1 and 2. Move the jumper to pins 2 and 3, leave for a few seconds and then reconnect to pins 1 and 2. This sometimes works.

You are not receiving a'beep' during the boot up. This indicates a problem which you may identify by trying to start in the safe mode or entering the start up and using Step by Step bootup. Before abandoning your PC try booting from your Windows Start up floppy disk and checking all connections (whilst disconnected from the mains) carefully.Your monitor is probably OK and can be checked by using the Menu controls on the screen buttons (usually) or simply connecting to a friends PC.